Guide system for an automotive vehicle with separate mobile transmitting device and method for controlling the vehicle

ABSTRACT

A golf cart or caddy and a mobile transmitting device carried by a golf player are each provided with a receiving and evaluating device equipped with a computer for a satellite-controlled positioning system. The two receiving and evaluating devices calculate the respective positions of the golf player and the golf caddy from the signals cyclically received from the satellite system. The mobile transmitting device is provided with a high-frequency manual transmitter which transmits, also cyclically, the positions of the golf player to the golf caddy. The computer of the golf caddy calculates direction and distance of the golf player and stores the data up to the time when the caddy follows the stored path upon a signal. The golf caddy stops at a predetermined distance from the golf player. When a stationary reference transmitter is additionally used for correcting the position data of the golf player and the golf caddy received from the satellite system, specific areas of the golf course can be excluded as forbidden areas, so that these will not be traveled by the golf caddy.

FIELD OF THE INVENTION

The present invention relates to a guide system for an automotivevehicle, in particular golf caddy, according to the preamble of patentclaim 1, wherein the vehicle can follow a mobile transmitting devicewhich, in the case of a golf caddy, is carried by a golf player, and canapproach the device up to a predetermined distance. The invention,however, is also applicable to other vehicles which are to follow amobile transmitting device automatically. Moreover, the inventionrelates to a method according to the preamble of claim 9.

BACKGROUND OF THE INVENTION

German patent specification 43 26 016 discloses an automotive vehicle,preferably a golf caddy, which comprises a high-frequency positionfinder and an ultrasonic position finder. When the golf caddy hasdetermined the direction of the hand-held transmitter by way ofhigh-frequency position finding, it will approach the transmitter on astraight path at a relatively high speed until it reaches an ultrasonicposition finding range in which ultrasonic position finding and reducedspeed are automatically switched to. Upon reaching a predeterminedminimum distance from the golf player, the golf caddy will stop.

The prior-art golf caddy has already proved to be a success in practice.A disadvantage of the combined high-frequency and ultrasonic positionfinding system is, however, that the golf caddy does not exactly followthe path which has been predetermined by the golf player with thehand-held transmitter, but approaches the path polygonally, which may bedisadvantageous, depending on the condition of the path. The automotivevehicle would not be able to follow a mobile transmitting device along asmall winding path, but could only approach such a path laterally,depending on the course of the track. Moreover, the prior-art systemdoes not offer the possibility of banning specific parts of the groundfor the automotive vehicle, since it would, for example, move into apond if the hand-held transmitter was at the other side of the pond andgave the signal "follow".

JP-Abstract 3-134715 A discloses a golf caddy which is equipped with asatellite-controlled positioning system (global positioning system GPS)for determining the exact position. The GPS serves to make visible theposition of different golf caddies on a display in a central office.

JP-Abstract 5-046079A also discloses a golf caddy with GPS which servesto store the distance traveled by a golf caddy in a memory using aperiodic timer and to display the respective positions of, and thedistances covered by, the golf caddy on a display by means of positioncoordinates of the golf course which are stored on a CD ROM.

U.S. Pat. No. 5,331,561 discloses a system wherein a vehicle withoutdriver follows a lead vehicle at a short predetermined distance on aroad. Both vehicles are equipped with a GPS receiver. Using lateralsensors, the lead vehicle gathers side range data which are given by therespective distance between the vehicle and lateral objects. Moreover,the distances which have so far been covered are measured with respectto the respective side range data. The lead vehicle transmits these datato the follower vehicle which also determines such side range profilesand compares these data with the transmitted data. If there aredeviations, the course of the follower vehicle will be corrected suchthat the side range data agree again.

U.S. Pat. No. 5,043,903 discloses a system for supporting the flyingmovements of helicopters or aircrafts which are flying in a formation.The document is concerned with positioning each aircraft within such aformation and with maintaining the mutual distances between theaircraft.

It is the object of the present invention to provide a guide system foran automotive vehicle which ensures exact guidance. Moreover, a methodfor exactly guiding a vehicle is to be indicated. Moreover, an improvedmethod for controlling the vehicle is to be indicated.

These objects are achieved according to the invention by the featuresindicated in patent claims 1 and 9.

Advantageous developments of the invention are characterized in thesubclaims.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, both the mobile transmitting deviceand the automotive vehicle comprise a receiving and evaluating deviceequipped with a computer for a satellite-controlled positioning system.The satellite positioning system includes, for instance, four satelliteswhich simultaneously send signals which are received and processed bythe positioning receivers. The computer of the receiving and evaluatingdevices determines the coordinates of the respective position from theintercepted signals.

The mobile transmitting device sends its coordinates to the vehicle, thecomputer of which converts these signals into information about the pathto be traveled, i.e. the direction of and distance from the transmitterare calculated.

Hence, the automotive vehicle, preferably a golf caddy, and the mobiletransmitting device which is carried by a golf player are in permanentcommunication with the satellites of a satellite navigation system, andthere is a constant data exchange via a radio path from the player tothe golf caddy, so that the caddy can calculate and store the respectiveposition data, i.e. the direction of and distance from the mobiletransmitting device.

When the golf player sends the signal "come" to the golf caddy, the golfcaddy will travel along the stored positions, exactly following the pathpreviously taken by the golf player. Hence, a golf caddy is, forinstance, able to follow a golf player, who is a long way ahead, over asmall bridge, because the path tracked by the golf caddy issubstantially identical with that of the player.

The mobile transmitting device is preferably provided with ahigh-frequency transmitter, which may be a hand-held transmitter. Withthe aid of this hand-held transmitter, a golf player will communicatehis respective position to the vehicle at regular intervals, preferablyevery second, with the computer of the vehicle converting the signalsinto data which will then serve as control signals for the motor, sothat the vehicle can follow the path of the transmitting device.

The vehicle should be equipped with sensors for detecting obstacleswhich are in its way. The sensors may make use of microwaves, ultrasonicwaves or infrared waves. When an obstacle located within the track issensed, the vehicle may be prompted to circumvent this obstacle along apredetermined track which is out of the obstacle's reach. Suchalternative tracks may be preprogrammed as suitable sets of curves.

As already mentioned, the position data of the transmitting device (golfplayer) which are transmitted via the radio path to the vehicle arestored in the computer of the vehicle up to the time when the vehiclereceives a START signal. Thereupon, the vehicle will exactly follow thepath of the mobile transmitter which is intermittently stored at shorttime intervals. At any time, the golf player can transmit a STOP signalto the vehicle, whereupon the latter will stop immediately. In theabsence of such a signal the vehicle will approach the mobiletransmitter (golf player) up to a predetermined distance, preferably setby the golf player, which will automatically be observed by the vehicle(golf caddy).

In another development of the invention, there may additionally beprovided a stationary receiving and evaluating device for thesatellite-controlled positioning device which sends correction signalsto the mobile transmitting device and/or the vehicle. Since thecoordinates of this stationary receiving and evaluating device arefixed, the error rate of the satellite navigation system can virtuallybe reduced to zero, since the position data of the mobile transmittingdevice and of the vehicle can be calculated with the aid of a so-calleddifferential method in the most accurate manner. The stationaryreceiving and evaluating device can, for example, be installed in theclubhouse of the golf course.

Specific areas, such as sand traps and water holes of a golf course, canbe excluded owing to the use of the stationary reference transmitter, sothat the golf caddy does not travel through such zones. When such a zoneis entered by a golf player, the golf caddy will remain at the border ofthe forbidden area or will circumvent the zone to follow thetransmitting device when the latter has again left the forbidden area.

The American GBS (Global Positional System) can, for example, be used asthe satellite navigation system, with another satellite navigationsystem, for instance the existing Russian satellite navigation system,being possibly used for increasing the accuracy of the position findingaction. When a reference transmitter is used, the accuracy of theposition finding action by way of the "differential method" is so highthat one of the existing satellite navigation systems is sufficient.

BRIEF DESCRIPTION OF THE DRAWINGS

The vehicle of the invention will follow the mobile transmitter in theopen field with maximum accuracy on the predetermined path, provided thetransmitter does not enter an excluded area which is forbidden to thevehicle. As a result, the vehicle of the invention is especially wellsuited in particular, but not exclusively, as a golf caddy.

The system according to the invention shall be briefly explained in thefollowing text with reference to two examples, wherein:

FIG. 1 diagrammatically shows the basic system; and

FIG. 2 diagrammatically shows a system of increased positional accuracy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The diagrammatic figures deal with a case where the system according tothe invention relates to a golf caddy 1 which is to follow a player 2.The receiving and evaluating devices (not shown) of the golf caddy 1 andthe mobile transmitting device (also not shown) of player 2 communicatewith a satellite system 3, consisting of at least four satellites, andreceive from the system signals which are converted by the computers ofthe receiving and evaluating devices into position data, such ascoordinates. Moreover, the high-frequency transmitter of player 2transmits its calculated position data to caddy 1, the computer of whichcompares the position data as received from the player with its ownposition data and calculates and stores distance and direction of therespective position of the player therefrom. Upon a START signal fromplayer 2, caddy 1 follows the stored position data.

The system shown in FIG. 2 additionally includes a stationary referencetransmitter 4 which also receives position data from the satellitesystem 3, so that the reference transmitter can calculate correctionposition data by comparing the position data as received with its fixedand known exact position data, with the correction position data beingsent by the transmitter to the computers of the vehicle 1 and the mobiletransmitter 2. As a result of the transmission, the computers cancalculate their own exact position data.

The receiving and evaluating device of vehicle 1 obtainsthe--corrected--position data of the player 2, so that the computer ofthe vehicle can calculate the direction of and distance from the player.These values are stored at an interval of one second.

When vehicle 1 receives a START signal from the player, it will followthe stored track until it has approached the player up to a pretermineddistance. At this distance, the vehicle will stop automatically.

It is within the scope of the present invention that vehicle 1 willfollow player 2 without receiving a START signal if the distance betweenvehicle and player exceeds a predetermined, adjustable minimum value.

What is claimed is:
 1. A guide system for an automotive vehicle, inparticular a golf caddy, wherein the automotive vehicle comprises adrive device, a control device and a signal receiving device, andwherein there is provided a mobile transmitting device which cantransmit position signals to the vehicle so that said vehicle can followthe mobile transmitting device, said mobile transmitting device and saidautomotive vehicle being each provided with a receiving and evaluatingdevice equipped with a computer for a satellite-controlled positioningsystem from which position data is computed whereupon the vehiclecompares the position data of said mobile transmitting device to theposition data of said vehicle and from which said vehicle calculates thedistance and the respective direction of said mobile transmitting deviceto said vehicle, said vehicle further storing said distance andrespective direction as a sequence of stored positions until saidvehicle follows said mobile transmitting device, said guide systemfurther comprising a stationary receiving and evaluating device for saidsatellite-controlled positioning system which sends correction signalsto either of said mobile transmitting device or said vehicle.
 2. Theguide system according to claim 1, wherein said mobile transmittingdevice further comprises a high-frequency hand-held transmitter.
 3. Theguide system according to claim 1 wherein said mobile transmittingdevice transmits a one Hertz signal indicative of its position to saidvehicle.
 4. The guide system according to claim 1 wherein said vehiclefurther comprises sensors for sensing obstacles positioned along itspath.
 5. The guide system according to claim 4, wherein the sensors areresponsive to a transmitter emitting a signal selected from the group ofmicrowave, infrared or ultrasonic signals.
 6. The guide system accordingto claim 1 wherein a memory of the receiving and evaluating device ofthe vehicle stores the position signals received from said mobiletransmitter up to the time when the vehicle travels through thepositions.
 7. The guide system according to claim 1 wherein the absolutecoordinates of areas banned from said vehicle are stored in the computerof said vehicle.
 8. A method for controlling an automotive vehicle,preferably a golf caddy, so that the vehicle can automatically follow amobile transmitting device and can approach said mobile transmittingdevice up to a predetermined distance, wherein the vehicle and saidmobile transmitting device receive signals sent by a satellite system atpredetermined time intervals, and calculate their respective positionstherefrom, and wherein said mobile transmitting device respectivelytransmits position signals indicative of said positions to the vehiclefrom which position data is computed, whereupon the vehicle compares theposition data of said mobile transmitting device to the position data ofsaid vehicle and from which the vehicle calculates the distance and therespective direction of the mobile transmitting device to the vehicle,the vehicle further storing said distance and respective direction as asequence of stored positions until the vehicle follows the mobiletransmitting device and wherein said vehicle follows the storedpositions upon a signal, characterized in that either of said mobiletransmitting device or said vehicle further receive position signalsfrom a stationary reference transmitter from which corrected, exactposition data is determined.
 9. The method according to claim 8,characterized in that the vehicle approaches the mobile transmittingdevice only up to a predetermined distance.
 10. The method according toclaim 8 wherein the vehicle stores the coordinates of a border offorbidden areas transmitted to said vehicle by said stationary referencetransmitter and said vehicle circumvents such an area when positions tobe traveled into lead through a forbidden area by remaining outside ofthe border of said forbidden area via a preprogrammed path.